It has been my experience that when you check in at the airport for your first segment, you are automatically waitlisted for all connecting segments.

When you arrive at your connecting airport, head directly to the gate to see if your upgrade has cleared. If not, you should be waitlisted based on your check-in time for your first segment. Ask anyway.

As to assistance from the Crown Room, some personnel are really helpful, others will tell you to check with the gate.

Hope this helps.